Hydroelectric fluid forming device

ABSTRACT

A MATERIAL WORKING APPARATUS INCLUDING A STATIONARY CHAMBER HAVING FLUID THEREIN AND ONE OR MORE PAIRS OF ELECTRODES IN THE FLUID TO ALLOW AN ELECTRICAL DISCHARGE BETWEEN THEM. ACROSS THE BOTTOM OF THE CHAMBER IS A FLEXIBLE DIAPHRAGM. A SECOND CHAMBER HAVING A FLEXIBLE DIAPHRAGM ACROSS ITS TOP AND BOTTOM IS LOCATED ADJACENT THE FIRST CHAMBER SO THAT PRESSURE PULSES DEVELOPED IN THE FIRST CHAMBER MAY BE PASSED THROUGH THE DIAPHRAGM INTO A FLUID IN THE SECOND CHAMBER AND THEN TO A MATERIAL WHICH IS TO BE FORMED. THE ENERGY APPLIED THROUGH THE SECOND CHAMBER MAY BE APPLIED TO A FLEXIBLE DIAPHRAGM WHICH IS ITS TURN IS USED TO PRESS THE MATERIAL BEING WORKED AND FORM IT IN SOME WAY AGAINST A DIE.

Jan.,26, 1971 P, M. ERLANDsoN 3,557,590 Y I HYDROELECTRIC FLUID FORMING DEVICE Filed Aug. 27, 1965 /NVENTOR PAUL M. E RLANDSON BY ATT'Y.

Jan. 26, 1971 P. M. ERLANDSQN l HYDROELECTRIC FLUID FORMING DEVICE 3 Sheets-#Sheet 2' Filed. Aug. 2"?. 1968 INVENTOR PAUL M. ERLA NDSON P. M. ERL'AN'psoN M Filed Aug...2,v. 196ef INVEN'TOR PAUL M." RLANDSON BY .EQ QQ'- AUnited i States Patent O1 ice 3,557,590 Patented Jan. 26, 1971 3,557,590 HYDROELECTRIC FLUID FORMING DEVICE Paul M. Erlandson, Palos Park, Ill., assignor to C011- tinental Can Company, Inc., New York, N.Y., a corporation of New York Filed Aug. 27, 1968, Ser. No. 755,641 Int. Cl. B21d 26/14 U.S. Cl. 72-56 15 Claims ABSTRACT F THE DISCLOSURE A material working apparatus including a stationary chamber having uid therein and one or more pairs of electrodes in the iluid to allow an electrical discharge between them. Across the bottom of the chamber is a flexible diaphragm. A second chamber having a exible diaphragm across its top and bottom is located adjacent the first chamber so that pressure pulses developed in the rst chamber may be passed through the diaphragm into a fluid in the second chamber and then to a material which is to be formed. The energy applied through the second chamber may be applied to a flexible diaphragm which in its turn is used to press the material being worked and form it in some Way against a die.

' Donald J. Roth, No. 3,267,780 issued Aug. 23, 1966, and

assigned to the assignee of the present invention. An earlier patent to Kemerer, No. 2,385,083 describes the use of fluid pressure impulses varying rapidly in intensity to mold the materials. The utility of these machines is limited -when applied to high speed operation because the force applying membrane of the driving chamber comes into direct contact with the element being formed. High speed machines employing rotating or reciprocating parts must have a rotatable driving chamber moving along with the element being formed in order to apply force to the element over a period of time sufficient to complete the forming operation. Use of an intervening chamber avoids friction and possible rupture of the diaphragm. It is readily apparent that hydraulic and electrical connections are difficult to maintain in a movable system having only one chamber and that connections between the electrical power and liquid source and the driving chamber make the cost of such a system high. My invention obviates the above diliculties by providing an energy transmission device between the stationary driving chamber and the material to be worked. The energy transmission device4 moves With the material being worked and is of similar acoustic impedance in order to obtain good energy transmission between them.

It is an object of my invention to provide an acoustic transmitting means between the driving chamber and the material to be worked.

It is another object of my invention to provide a movable transmitting chamber between the stationary driving chamber and the object to be worked.

It is another object of my invention to provide a movable chamber which allows the redirection of pressure waves in said chamber.

It is a final object of my invention to provide a hydroelectric fluid device for cutting, forming molding or laminating a moving workpiece at high speed operation.

In brief, my invention comprises a stationary driving chamber containing a fluid and a source of a pressure wave and a movable driven pressure transmitting means. The movable driven means may contain a fluid and have one or more ilexible membranes, or flexible surfaces at least one of which is a flexible wall of the driving chamber. An impulse is developed in the driving chamber and is passed through the open surface of the driving chamber to the driven means and from the driven means the impulse may work a material against a die to form a surface of the material in accordance with the shape of the die.

More detailed aspects of this invention will become more apparent from the following description taken in conjunction with the accompanying drawings.

FIG. l is a showing of the apparatus embodying the principles of my invention.

FIG. 2 shows an embodiment of my invention wherein the driven chamber has means for the redirection of the pressure waves.

FIG. 3 shows my invention applied to a cutting die.

FIG. 4 shows my invention utilizing a cup and endless belt.

FIG. 5 shows an embodiment of my invention adapted for forming a cup shaped workpiece and featuring a rotatable turret.

Shown in FIG. 1 is an embodiment of my invention having a driving chamber 10 and a driven chamber 30. The driving chamber may be of substantially any size or shape and is shown as an inverted cup 1. Shock and/or pressure waves are developed inside inverted cup 1 by electric arcing between electrodes 2 and 4 located substantially axially in the cup. IElectric current is conducted through insulator plug 3, to electrode 2. Electric current is also conducted to inverted cup 1. Insulator plug 3 is made of a nonfrangible material while cup 1 is made of a nonfrangible conductive material. Cup 1 is electrically connected to electrode ring 4. lElectrode 4 is mounted about the central electrode 2 in such way that the path of least electrical resistance is from electrode 2 through liquid 5 to electrode ring 4. In this way suicient applied electric potential causes an arc between electrodes 2 and 4. Cup 1 may be made of any desired nonfrangible conductive material, however, the path of least electrical resistance must be between electrode 2 and electrode ring 4 so that current flow is between these electrically conductive elements to form an arc. These electrodes are connected to an electrical power supply 6 positioned at any convenient location and the electrical power supply is capable of delivering controlled electrical impulses of high voltages and current. Mounted across the open side of the inverted cup is a exible membrane 7 held in place by ring 8.

Driven chamber 30 has a similar outside diameter to driving chamber 10 and is positioned below driving chamber 10 having at its upper end a exible membrane 9 and at its lower end a flexible membrane 11. These flexible membranes are held in place by retaining rings 12 and 13, respectively. Inside the dri-ven chamber 30 is a iluid 14 of acoustic impedance similar to` that of the iluid 5 inside driving chamber 10. The upper exible membrane 9 of the driven chamber is located adjacent the flexible membrane 7 of the driving chamber and the boundaries of the membranes are coextensive so that the impulses from the upper chamber are transmitted through the lower chamber and are not lost around the edges of the membranes. In this 'way impulses from uid 5 are passed through the flexible membranes 7, 9 into iluid 14 of the driven chamber and to the lower membrane 11 of the driven chamber to move the lower membrane and apply force to workpiece 15 adjacent and outside of lower membrane 11.

Workpiece 15 is positioned next to flexible membrane 11 and located on the other side of the `workpiece is a die 16 of some configuration. When an impulse is given off between electrodes 2 and 4 a shock or pressure wave travels through iluid 5, fluid 14 and lower membrane 11 and presses 'workpiece 15 against die 16'. The die 16 may be given any desired shape to accomplish beading, embossing or cut-off as may be appropriate to the desired effect.

The acoustic length of the two chambers 10, 30 may be varied by varying the length of the driven chamber 30 to obtain a resonant cavity condition for a particular hydroelectric impulse as desired.

Two devices for redirecting the course of propagation of pressure waves through the fluid medium are shown in FIG. 2. Redirection of the wave front may be achieved by an acoustic lens 16 or alternatively by a reflecting surface 17. Driving chamber 10 of FIG. 2 is essentially the same as driving chamber 10 of FIG. l. The acoustic lens 16 of FIG. 2 forms part of the upper section of driven chamber `50 and may have a variety of shapes depending upon whether convergence or divergence of waves is desired in the forming operation. As shown in FIG. 2 acoustic lens 16 is plano-concave and is made of a foam rubber or some other elastomeric material having a different acoustic impedance from that of the fluids 5 and 14. A pressure impulse is developed in driving chamber 10. This causes membranes 7 and 8 to move downwardly until they assume the shape of the top of the plano-concave lens 16. The lower margin 17 of the membranes 8 strikes the lens top with force thus imparting a pressure wave to the top of the lens. The pressure wave passes through lens 16 where its direction is altered and then into fluid 14 and down toward the reflecting surface 17 at the bottom of the driven chamber. In the embodiment shown, a workpiece 19 surrounds the flexible membranes 20 of the lower chamber. The thin-walled cup-shaped workpiece 19 located outside of the membrane 20 has about it a forming die 21. When an impulse is developed between the electrodes 2 and 4, the pressure wa-ve is conducted through fluid 5, through membranes 7 and 8 dellecting these membranes and passes through acoustic lens 16. As shown by arrows, the wave then passes from the lens toward the bottom of the chamber. At the bottom of the chamber the dellector element 17 reflects the waves from its surface to travel in a radial direction toward the workpiece 20. In this way a pressure wave originating in the space between the electrodes 2 and 4 passes downwardly and is reflected radially or outwardly against the side of cup-shaped impulse membrane 20. The cup-shaped membrane is forced against workpiece 19 which now forms into the contours of die 21 to give a final cup-shaped workpiece having the desired imprinting. The lens 16 or reflector 17 may be made of any desired contour in order to divert the course of the impulse wave in the direction that may be desired in the particular application of my invention.

The die 21 mounted about this apparatus may be integral or may be split for easier removal of the expanded workpiece from the die.

An embodiment of my invention arranged for use as a die cutter for flat stock is shown in FIG. 3. In this embodiment flat stock material 22 is fed by belt 23 to cutting element 24. Flexible belt 23 presses against stock material 22 and moves with it. After a predetermined length of flat stock has passed the cutting edge of element 24, an electric discharge is released across the arc gap 2, 4. A friction reducing material may be introduced between endless belt 23 and diaphragm 7 so that friction between belt 23 and diaphragm 7 is kept to a minimum and energy transmission between chambers is heightened.

After a predetermined amount of blank stock 22 has traversed die cutting element 24 pulse source 6 applies a pulse of electricity across electrodes 2 and `4 to give rise to a pressure impulse. Flexible belt 23 has about the same acoustic impedance as impulse transmitting lluid 5 and a maximum impulse passes through the flexible belt 23 which presses against the flat stock 22 to cause a quick shearing of the blank stock. The cut piece may be transported for further operations.

If desired the membrane 8 may be deleted without substantial loss of elliciency. Efficiency may actually be improved by eliminating membrane 8 depending upon the materials involved.

The embodiment as shown in FIG. 4 and the flexible belt 25 serves the purpose of retaining liquid in the chamber as well as acting as a force transmitting agency. Force transmitting liquid 5 is replenished in cup 1 to keep the cup filled and avoid undue softening of the shock impulse by air in the driving chamber. Driving chamber 10 is shown with its open side turned up to avoid spillage, however, the cup may be oriented against the belt in almost any position without substantial loss of liquid. Rotating die 26 is shown in the form of a wheel which may contain a cut-off die and various beading and embossing figures in a recurring design.

FIG. 5 shows a schematic diagram of one embodiment of my invention wherein the element to be formed is mounted on a rotary arm 27 and is rotated on a turret or base 28. The element 29 to be formed may be reciprocated or rotated to and from the working position l along with the driven chamber 30 and the are is fired only when the driving and driven chambers are in registry with each other. The impulse generating or driving chamber 10 is fixed in position to allow most efficient and economical operation of power supply 6. Electrical control circuits 31 and energy storage capacitor 32 form power supply 6. The energy storage capacitor 32 is connected for discharge to electrode 2 through a low inductive lead 33 in the fixed driving chamber 10. Electrode 4 is connected (not shown) to the other side of the energy storage capacitor 32 so that when the electrical Circuit from the capacitor to the electrodes is closed and the energy storage capacitor is allowed to discharge an electric arc of some magnitude is developed between electrodes 2 and 4. The energy storage capacitor 32 fires periodically at such times as the moving chamber 30 is directly underneath the fixed chamber 10 and in registry with it.

Although only one moving chamber is shown, it is understood that additional chambers may be provided on individual arms rotating about the base 28. The split die 34 shown is removed at later stages of the operation and may be reassembled for further use. Arm 27 may be rotating or reciprocating depending on the mode of operation. Any of the driving or driven chambers or belts shown in FIGS. 1-4 may be used in FIG. 5 if so desired without departing from the spirit of my invention. One or more pairs of electrodes may be used as desired for multiple waves.

A principle advantage of my invention is that the power source and driving chamber are maintained in a stationary position to give a constant force generated by the driving chamber in an efllcient manner. Other advantages are that the chambers may be shaped independently of each other, the impedances of various elements may be matched for control of force transmission between them and the effective chamber length may be varied to correspond to the wave length and frequency of the impulses to give a resonant cavity.

Any combination of the shown driving and driven chambers is within the scope of my invention.

The foregoing is a description of illustrative embodiments of the invention, and it is applicants intention in the appended claims to cover all forms which fall within the scope of the invention.

What is claimed is:

1. A hydroelectric forming device comprising:

a closed driving chamber having at least one substantially flat side and a flexible member extending across said side to close said chamber and having electrodes mounted within said chamber and said chamber being tilled with a liquid for transmitting pressure waves from the vicinity of said electrodes to said membrane, and

means movable across the face of said flexible member and mounted adjacent said driving chamber for transmitting said pressure waves from said driving chamber to a workpiece.

2. A hydroelectric forming device as set forth in claim 1 in which:

said means movable across the face of said flexible member comprises:

an endless belt made of a material having an acoustic impedance similar to that of the transmitting liquid of said driving chamber.

3. A hydroelectric forming device as set forth in claim 1 in which:

said means movable across the face of said flexible member comprises:

a movable chamber having two openings and a membrane across one opening coextensive with the membrane of said driving chamber, and

a second membrane mounted across the other opening of said chamber and fluid in said driven chamber whereby said shock waves are transmitted from one membrane to the other through said fluid.

4. A hydroelectric forming device as set forth in claim 3 in which:

said means movable across the face of said exible member further comprises:

` an acoustic lens mounted within said driven chamber whereby the direction of shock impulse waves generated within said driving chamber is refracted and their course changed upon passing through said lens.

5. A hydroelectric forming device as set forth in claim 4 in which:

said means movable across the face of said liexible member further comprises:

a means mounted in the path of said refracted shock waves for reecting said waves to a new direction.

6. A hydroelectric forming device as set forth in claim 3 in which:

said means movable across the face of said flexible member comprises:

a means mounted in the path of said shock waves for reflecting said waves to a new direction.

7. A hydroelectric forming device as set forth in claim 5 in which:

said second membrane extends around all but one side of said movable chamber.

8. A hydroelectric forming device as set forth in claim 3 in which:

said closed driving chamber is mounted upon a xed supporting means,

electrical energy generating and releasing means is electrically connected to said electrodes whereby at intervals electrical potential is applied across said electrodes to cause an arc to pass between said electrodes.

9. A hydroelectric forming device as set forth in claim 8 in which:

said means movable across the face of said flexible member comprises:

a plurality of chambers mounted upon a movable means for indexing each of said chambers one at a time adjacent said drive means with the membranes of said drive and driven chambers in opposition so that said shock impulse is transmitted through said drive means and through said first membrane of said driven means to said second membrane of said driven means.

10. A hydroelectric forming device as set forth in claim 9 in which:

said driven chambers are of different lengths to form resonant cavities for different wave lengths emanating from said arc.

11. A hydroelectric forming device as set forth in claim 3 in which:

a die is mounted in contact with the workpiece whereby pressure exerted by said driven chamber against said die presses said workpiece against said die to give said workpiece a new form.

12. A hydroelectric forming device comprising:

a driving chamber having one open side,

electrodes mounted within said driving chamber and -being electrically connected to a power source,

a liquid lilling said driving chamber, and

an endless belt made of a material having an acoustic impedance similar to that of the transmitting liquid of said driving chamber and a portion of said belt being disposed in sealing relationship across the open side of said driving chamber whereby shock impulses generated between said electrodes are passed through said liquid and said portion of said belt.

13. A method of transmitting shock waves for forming metal workpieces comprising the steps of:

generating a pressure impulse in a driving means,

transmitting said pressure impulse through a liquid in sad driving means to a means movable across the face of said flexible member adjacent said driving means,

guiding said shock impulse through said means movable across the face of said flexible member to a workpiece located adjacent said movable means,

moving said movable means across the pressure transmitting face of said driving means, and

pressing said workpiece into a die mounted adjacent said workpiece.

14. The method of transmitting shock waves for forming metal workpieces as set forth in claim 13 in which: said step of guiding said shock impulse comprises the additional steps of reliecting said shock impulse from its course to impact upon said workpiece in a direction at an angle to the direction of its initial course.

1S. The method of transmitting shock waves for forming metal workpieces as set forth in claim 13 in which: said step of transmitting said shock impulses comprises the additional steps of:

indexing each of a series of means movable across the face of said flexible member adjacent said drive means one by one whereby a shock impulse may be transmitted from said drive means to each said means movable across the face of said flexible member one at a time.

References Cited UNITED STATES PATENTS 3,195,334 7/1965 Filler 72--56 3,289,447 12/ 1966 Amini et al 72-56 3,225,578 12/1965 Krieger 72-56 3,267,780 8/1966 Roth 72-56 3,438,125 4/1969 Larsen et al. 72-56 3,447,350 6/ 1969 Schenk 72--56 RICHARD l. HERBST, Primary Examiner U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTIGN Patent No. 3"557,590 Dated January 26, 1971 Inventor) Paul M. Erlandson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The title should be Electrohydraulic Fluid Forming Device Column l, lines 28, 68 and 69 "a hydroelectric" should be an electrohydraulic Column 4, line 7l,- Column 5, lines 8, l5, 26 34 46 50 and 58; and Column 6, lines l, 6, l2 "A hydroelectric" should be An electrohydraulic Signed and srarziled this 1??,11 day of- Auguat 1 971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents FORM IPO-1050 (ID-69) 

